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All LessonsFree Lessons (4)

Introduction

Who Is This Course For?Hurdles in Learning An Insight on Existing Learning Material Why This Course?

Origins of the OS

Operating Systems Electromechanical Computer Relay Computers Electrical Computers OS in Commercial Computers

Operating Systems

How the OS Works Application Programming Interface Computer Devices OS Features Multitasking Multiprogramming GUI: An Overview GUI: TTY and CLI GUI: TUI and Xerox OS Versions OS: Windows OS: Linux

Application

Computer Program Levels of Computer Memory Machine Code Exercise: Number Conversions Source Code Compiler Interpreter

Bash Shell

Development Tools Command Interpreter Command-line Interface

File System

Directory Structures File System Navigation Commands Command pwd The ls Utility The mount Utility Command cd Command history The find Utility Using Glob Pattern with the find Utility Advanced Usage of the find Utility Logic Expressions The grep Command echo and grep

Command Information

Man Page System and Command help Info System and Brief Help

Files and Directories

Actions on Files and Directories The mkdir Utility The rm Utility The cp and mv Utilities Exercise: Commands File System Permissions Unix Permissions File Execution Installing and Running Applications in Bash

Bash Extra Features

Unix Design Philosophy GNU Utilities I/O Redirection Pipelines Advanced Pipeline Example Limitations of the find Utility The xargs Utility Pipeline Pitfalls Logical Operator AND More on Operators Combining Commands Exercise: Bash Features

Scripts Features

Why Do We Need Scripts?Backup Command Example Verifying the Backup Command Poor Technical Solution Using Bash Script Commands Sequence Script Parameters Script with Other Commands Summary

Variables and Parameters

What are Variables?

Classification of Variables

Declaration Mechanism: User-Defined Variables

Bash Expansions

Exercise: Writing a Bash Script

Declaration Mechanism: Internal Variables

Declaration Mechanism: Special Parameters

Scope: Environment Variables

Scope: Local Variables

Content Type: Variable Attributes

Declaring Variables with Attributes

Composite Type: Indexed Arrays

Using Indexed Arrays

Practice: Indexed Arrays

Composite Types: Associative Arrays

Conditional Statements

If Statement If-else Statement Exercise: If Statement The [[ Operator Advanced Features of the [[ Operator Operator [[ and Integers Exercise: Operator [[Exercise: The [[ Operator and Directories Case Statement if and case Statements Exercise: Case Statement Alternative to the Case Statement Exercise: Case Statement and Associative Array

Arithmetic Expressions and Operations

Integer Representation Sign-magnitude Representation One's Complement Two's Complement Converting Numbers The (( Operator Operations in the Arithmetic Expressions Arithmetic Operations

Bitwise Operations

Bitwise negation Exercise: Bitwise NOT Bitwise AND, OR and XOR Exercise: Bitwise AND, OR, and XOR Bit Shifts Exercise: Bit shifts Changing Byte Order Using Bitwise Operations More on Using Bitwise Operations

Logical Operations and Increments

Logical Operations Increment and Decrement Ternary Operator

Loop Operators

Loop Constructs While Statement Infinite Loop Reading a Standard Input Stream Script for Managing the Contacts For Statement: The First Form of For Files Processing For Statement: The Second Form of For Controlling the Loop Execution: break Controlling Loop Execution: continue Exercise: Loop Constructs

Functions

Programming Paradigms Using Functions in Shell Functions and Aliases Difference Between Functions and Aliases Using Functions in Scripts Returning a Function Result Variable Scope Exercise: Functions Exercise: Variable Scope General Recommendations on Functions

Package Manager

Repository Operating on Packages

Conclusion

Course Assessment

Bash Programming from Scratch

Bash Scripts Tools

Tools Needed for Bash Source Code Editor Launching the Editor Background Mode

APPENDIX

Bash on Windows Bash on macOS

The Complete Guide to Bash Programming/

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What are Variables?

What are Variables?

Learn why and when you need variables.

We'll cover the following...

Variable definition
Need for variables

We already came across Bash variables several times in this course. We learned the list of system paths in the PATH variable. Then, we used positional parameters in the backup script. It’s time to get a good grasp on this topic.

Variable definition

Let’s start with the meaning of “variable” in programming. A variable is an area of memory where some value is ...